Photovoltaics are set to satisfy over 40% of Switzerland’s electrical energy wants by 2050. However solar energy is not at all times out there when it is wanted: there’s an excessive amount of of it in summer season and too little in winter, when the solar shines much less typically and warmth pumps are working at full tilt. In keeping with the Swiss federal authorities’s Vitality Technique, Switzerland needs to shut the winter electrical energy hole with a mix of imports, wind and hydropower in addition to alpine photo voltaic vegetation and gas-fired energy vegetation.
One strategy to decrease the necessity for imports and gas-fired energy vegetation in winter is to provide hydrogen from low-cost solar energy in summer season, which may then be transformed into electrical energy in winter. Nonetheless, hydrogen is extremely flammable, extraordinarily unstable and makes many supplies brittle.
Storing the gasoline from summer season till winter requires particular pressurized containers and cooling expertise. These require lots of power, whereas the numerous security precautions that should be adopted make constructing such storage amenities very costly. What’s extra, hydrogen tanks are by no means fully leak-proof, which harms the setting and provides to the prices.
Now researchers at ETH Zurich led by Wendelin Stark, Professor of Useful Supplies on the Division of Chemistry and Utilized Biosciences, have developed a brand new expertise for the seasonal storage of hydrogen that’s a lot safer and cheaper than current options. The researchers are utilizing a well known expertise and the fourth most ample component on Earth: iron.
The findings are revealed within the journal Sustainable Vitality & Fuels.
Chemical storage
To retailer hydrogen higher, Stark and his group are counting on the steam-iron course of, which has been understood because the nineteenth century. If there’s a surplus of solar energy out there in the summertime months, it may be used to separate water to provide hydrogen. This hydrogen is then fed into a chrome steel reactor crammed with pure iron ore at 400 levels Celsius. There, the hydrogen extracts the oxygen from the iron ore—which in chemical phrases is just iron oxide—leading to elemental iron and water.
“This chemical process is similar to charging a battery. It means that the energy in the hydrogen can be stored as iron and water for long periods with almost no losses,” Stark says.
When the power is required once more in winter, the researchers reverse the method: they feed sizzling steam into the reactor to show the iron and water again into iron oxide and hydrogen. The hydrogen can then be transformed into electrical energy or warmth in a gasoline turbine or gasoline cell. To maintain the power required for the discharging course of to a minimal, the steam is generated utilizing waste warmth from the discharging response.
Low-cost iron ore meets costly hydrogen
“The big advantage of this technology is that the raw material, iron ore, is easy to procure in large quantities. Plus it doesn’t even need processing before we put it in the reactor,” Stark says. Furthermore, the researchers assume that enormous iron ore storage amenities might be constructed worldwide with out considerably influencing the worldwide market value of iron.
The reactor during which the response takes place does not have to meet any particular security necessities both. It consists of stainless-steel partitions simply 6 millimeters thick. The response takes place at regular strain and the storage capability will increase with every cycle.
As soon as crammed with iron oxide, the reactor could be reused for any variety of storage cycles with out having to switch its contents. One other benefit of the expertise is that the researchers can simply develop the storage capability. It is merely a case of constructing larger reactors and filling them with extra iron ore. All these benefits make this storage expertise an estimated ten instances cheaper than current strategies.
Nonetheless, there’s additionally a draw back to utilizing hydrogen: its manufacturing and conversion are inefficient in comparison with different sources of power, as as much as 60% of its power is misplaced within the course of. Which means that as a storage medium, hydrogen is most tasty when ample wind or solar energy is offered and different choices are off the desk. That’s particularly the case with industrial processes that may’t be electrified.
Pilot plant on the Hönggerberg campus
The researchers have demonstrated the technical feasibility of their storage expertise utilizing a pilot plant on the Hönggerberg campus. This consists of three stainless-steel reactors with a capability of 1.4 cubic meters, every of which the researchers have crammed with 2–3 metric tons of untreated iron ore out there in the marketplace.
“The pilot plant can store around 10 megawatt hours of hydrogen over long periods. Depending on how you convert the hydrogen into electricity, that’ll give you somewhere between 4 and 6 megawatt hours of power,” explains Samuel Heiniger, a doctoral pupil in Stark’s analysis group. This corresponds to the electrical energy demand from three to 5 Swiss single-family properties within the winter months. At current, the system continues to be working on electrical energy from the grid and never on the solar energy generated on the Hönggerberg campus.
That is quickly set to vary: the researchers need to develop the system such that by 2026, the ETH Hönggerberg campus can meet one-fifth of its winter electrical energy necessities utilizing its personal solar energy from the summer season. This may require reactors with a quantity of two,000 cubic meters, which may retailer round 4 gigawatt hours (GWh) of inexperienced hydrogen.
As soon as transformed into electrical energy, the saved hydrogen would provide round 2 GWh of energy. “This plant could replace a small reservoir in the Alps as a seasonal energy storage facility. To put that in perspective, it equates to around one-tenth of the capacity of the Nate de Drance pumped storage power plant,” Stark says. As well as, the discharging course of would generate 2 GWh of warmth, which the researchers need to combine into the campus’s heating system.
Good scalability
However may this expertise be harnessed to supply seasonal power storage for Switzerland as a complete? The researchers have made some preliminary calculations: offering Switzerland with round 10 terawatt hours (TWh) of electrical energy from seasonal hydrogen storage techniques yearly sooner or later—which might admittedly be loads—would require some 15–20 TWh of inexperienced hydrogen and roughly 10,000,000 cubic meters of iron ore.
“That’s about 2% of what Australia, the largest producer of iron ore, mines every year,” Stark says. By means of comparability, in its Vitality Views 2050+, the Swiss Federal Workplace of Vitality anticipates whole electrical energy consumption of round 84 TWh in 2050.
If reactors had been constructed that might retailer round 1 GWh of electrical energy every, they might have a quantity of roughly 1,000 cubic meters. This requires round 100 sq. meters of constructing land. Switzerland must construct some 10,000 of those storage techniques to acquire 10 TWh of electrical energy in winter, which corresponds to an space of round 1 sq. meter per inhabitant.
Extra data:
Samuel P. Heiniger et al, Protected seasonal power and hydrogen storage in a 1 : 10 single-household-sized pilot reactor based mostly on the steam-iron course of, Sustainable Vitality & Fuels (2023). DOI: 10.1039/D3SE01228J
Quotation:
Pilot plant demonstrates iron-based hydrogen storage feasibility (2024, August 31)
retrieved 31 August 2024
from https://techxplore.com/information/2024-08-iron-based-hydrogen-storage-feasibility.html
This doc is topic to copyright. Other than any honest dealing for the aim of personal examine or analysis, no
half could also be reproduced with out the written permission. The content material is offered for data functions solely.